EP3536479B1 - Method and device for expanding and simultaneously filling containers - Google Patents

Description

The present invention relates to a device and a method for producing liquid containers and in particular beverage containers. Such methods have long been known from the prior art. In conventional processes, heated plastic preforms are first expanded into plastic bottles, which is done, for example, in blow molding machines. These expanded containers are then filled with a product such as a drink.

• Dokument WO 2017/090340 A1 zeigt ein Flüssigkeitsblasformverfahren zum Formen eines Behälters 60 aus einem Vorformling 2. In einem Füllschritt ist dabei eine erste Druckerzeugungsquelle 32 mit einer ersten Flüssigkeit L1 gefüllt und eine zweite Druckerzeugungsquelle 35 mit einer zweiten Flüssigkeit L2. Weiterhin wird in einem Formschritt der Vorformling 2 durch gleichzeitiges Betätigen der ersten Druckquelle 32 und der zweiten Druckquelle 35 flüssiggeblasen, wobei gleichzeitig die erste Flüssigkeit L1, die von der ersten Druckquelle 32 mit einem vorbestimmten Druck beaufschlagt wurde, und die zweite Flüssigkeit L2, die von der zweiten Druckquelle 35 mit einem vorbestimmten Druck beaufschlagt wurde, in den Vorformling 2 eingebracht wird.
• Dokument EP 2 987 619 A1 zeigt eine Formfüllmaschine sowie ein Verfahren zur Herstellung eines Kunststoffbehälters und dessen Befüllung mit mindestens einem Füllprodukt. Das zumindest teilweise Herstellen des Kunststoffbehälters durch Beaufschlagen des Preforms erfolgt dabei mit einem Füllprodukt mit einer ersten Temperatur, wobei der Kunststoffbehälter innerhalb der Form zumindest teilweise mit einem Füllprodukt mit einer zweiten, niedrigeren Temperatur befüllt wird.

Such devices are known from the prior art:

• document WO 2017/090340 A1 shows a liquid blow molding method for molding a container 60 from a preform 2. In a filling step, a first pressure generating source 32 is filled with a first liquid L1 and a second pressure generating source 35 is filled with a second liquid L2. Furthermore, in a molding step, the preform 2 is blown liquid by simultaneously actuating the first pressure source 32 and the second pressure source 35, the first liquid L1, which has been subjected to a predetermined pressure by the first pressure source 32, and the second liquid L2, which is supplied by the second pressure source 35 has been subjected to a predetermined pressure, is introduced into the preform 2.
• document EP 2 987 619 A1 shows a form filling machine and a method for producing a plastic container and filling it with at least one filling product. The at least partial production of the plastic container by loading the preform takes place with a filling product at a first temperature, the plastic container within the mold being at least partially filled with a filling product at a second, lower temperature.

More recently, devices and methods have also become known in which plastic preforms are filled directly with the filling material to be filled and are also expanded in the process. For this purpose it is known that a pressure generating device or pressure application device, such as a pump or a piston, is used to generate the pressure with which the liquid filling material is filled into the plastic preform to be expanded. For this purpose, very high powers are sometimes required for the drives of such pistons. Sometimes it is also desirable not to fill the containers with a pure product, but with a product mixture.

At present, a molding unit is used for molding containers with a liquid medium, which then remains in the container, which is roughly composed of two subassemblies. These assemblies are defined on the one hand by a filling cylinder (in the following also pressure generation unit) and on the other hand by a filling head (in the following filling device). The filling cylinder is single-acting in the prior art and is carried out via a supply line from a central fluid reservoir supplied with a liquid medium, in particular the filling material. In the prior art, the supply line between the central liquid reservoir and the filling cylinder can be shut off by a shut-off device.

When the filling cylinder is filled, the shut-off device is closed and the flow is blocked. During a molding process, the liquid medium is pressed from the filling cylinder into the filling head.

The connection between the filling cylinder and the filling head is designed with at least one channel, these channels not being able to be shut off in the prior art. A constant flow from the filling cylinder to the filling head is possible at any time.

The filling head is placed on the plastic preform before the molding process and in particular also seals the interface to the plastic preform. In the prior art, the filling head is tightly closed by a sealing plug.

After a pre-pressure has been set in the filling head, in particular through the movement of the filling piston, the sealing plug is opened. The forming process begins with this step, with the plastic preform being formed into a container under the action of the liquid medium and possibly also a stretching rod.

In order to be able to optimally reproduce the contour of this shape on the container, a period of time with a constant internal container pressure (pressure holding time) is required, which is realized in the prior art by the piston being at a standstill.

The present invention is based on the object of making such devices and methods more efficient and also more versatile. If possible, the high peak outputs for pressure generating devices should also be reduced. According to the invention, these objects are achieved by the subject matter of the independent patent claims. Advantageous embodiments and developments are the subject of the subclaims.

A device according to the invention for expanding plastic preforms into plastic containers by means of a liquid medium has at least one reshaping station on, which fills the plastic preforms with the liquid medium and expands. Furthermore, the device has at least one feed device which feeds the liquid medium to a filling device of this reshaping station, this filling device being suitable and intended for filling the liquid medium into the plastic preforms, and wherein the device has a pressure generating device which supplies the liquid medium to the filling device feeds under pressure.

According to the invention, the pressure generating device has at least two pressure generating units which are suitable and intended to provide and / or supply the liquid medium under pressure to the reshaping station.

It is therefore proposed that, instead of the one pressure generating unit usually used in the prior art, two pressure generating units or even several

Pressure generating units are used. This offers different advantages. For example, the variability is increased because the two pressure generating units can also supply different products. In this way, the performance requirements for only one pressure generation unit are reduced and these can be dimensioned smaller or can also be operated with lower power.

In the context of the present application, the forming station is understood to mean the entire device, which in particular also has at least one pressure generating device and at least one filling device. The filling device is understood to mean that component of the device which fills the liquid into the respective container.

In a further advantageous embodiment, the device has a plurality of such forming stations. It is possible and preferred for each of these forming stations to be assigned two or, if necessary, also several pressure generating units. The device preferably has a carrier on which the forming stations are arranged. In particular, it can be a rotatable carrier and in particular a carrier rotatable about a predetermined axis of rotation, on the outer circumference of which the forming stations are arranged. However, it would also be conceivable for the forming stations to be transported at least in sections along a straight transport path. The forming stations could, for example be arranged on a revolving chain. It would also be conceivable for the forming stations to be transported in a straight line or for the containers to be introduced into, or transported to, stationary forming stations.

In a further preferred embodiment, the reshaping station has a reshaping mold within which the plastic preforms can be arranged in order to expand them with the liquid product. These reshaping molds can be designed in such a way that the plastic preforms are expanded against the inner walls of these reshaping stations.

In a further advantageous embodiment, the device has a pressure measuring device which at least intermittently measures a pressure of the medium to be filled. This pressure measuring device can be arranged, for example, on a filling head (that is to say in particular in an area of the filling device).

In a further advantageous embodiment, the device has a contact device in order to apply the filling head to the respective plastic preform.

In a further preferred embodiment, the reshaping station has a stretching rod which can be introduced into the interior of the plastic preforms in order to stretch them in their longitudinal direction. It is also possible that this stretching rod is designed as a hollow body and has a channel inside for conducting a flowable, in particular liquid, medium.

In the prior art, the problem sometimes arises that the liquid to be filled cools a plastic preform more quickly than air and, in this way, very high filling speeds are necessary in order to expand the plastic preform. This is because the plastic preform should be deformed while it is still as hot as possible, in particular in order to avoid stress whitening. For example, with a 1.5 l bottle, an average volume flow of 15 l / sec would be necessary in 0.1 seconds, which in turn means a relatively high load with regard to the drive dimensioning of the pressure generating device. The nominal widths of the components are also kept very high due to the very high volume flow.

In order to find a drive with larger containers despite everything that still has torque reserves, a different concept would have to be used. If even larger bottle types are to be produced, higher volume flows must be achieved. In addition, the back pressure of the head and the components through which it flows increases due to the higher flow velocity. This also means that the drive has to handle higher loads. These two relationships are contradicting each other and can therefore lead to major problems when optimizing the drive, since components that can handle higher loads usually also have a higher level of inertia and thus cannot realize higher dynamics.

The present invention overcomes this problem by providing two pressure generating devices which on the one hand can jointly produce the respective pressure level and / or the necessary total volume flow, but on the other hand it is also possible to dispense with particularly heavy components.

It is therefore proposed, as mentioned above, that the pressure generation is not carried out by a single drive or by a pressure generation unit, but rather by several and in particular by several at the same time. As mentioned in more detail below, this can be useful for pumps as well as for piston / cylinder drives. The requirements of the respective drives with regard to dynamic load, diameter of the piston are significantly lower if these requirements are met in particular by a clever parallel connection or, if necessary, also in series connection of the drive components.

In a further advantageous embodiment, the two pressure generating units are connected in parallel in such a way that they can feed the liquid medium to the forming station together and can preferably also feed it at the same time. It is possible that the two pressure generating units are operated in parallel, that is to say controlled in the same way. It would also be possible for the pressure generating units to be controlled differently in order to be able to meet different pressure and volume flow requirements during the filling and expansion process, for example. In addition, however, a series connection of the pressure generating units would also be possible.

In a further preferred embodiment, the at least two pressure generating units or both pressure generating units are each connected to the filling device via liquid lines. These are preferably partially separate and preferably completely separate fluid lines which each connect the two pressure generating units to the filling device, that is to say in particular to the filling head. In this way, the liquid can be fed to the filling device via these two separate feed lines.

The pressure generating units also preferably have at least partially and preferably essentially completely separate feed lines, which in turn feed them (in particular starting from a reservoir) with the liquid (to be filled).

In a further advantageous embodiment, the filling device has a collecting space for receiving the liquid medium. The above-mentioned liquid lines can open into this collecting space. Particularly preferably, the two feed lines open in the collecting space at different positions, for example at different positions in a circumferential direction of the filling device. This circumferential direction can be defined, for example, with respect to the longitudinal direction of the plastic preforms to be expanded.

In a further preferred embodiment, the filling device has a collecting space for receiving the liquid medium. This collecting space is at least temporarily in flow connection with each of the pressure generating units. In this case, however, it would be possible for valves to be provided between the collecting space and the pressure generating device which can control a product flow from the respective pressure generating unit to the collecting space.

In a further advantageous embodiment, the pressure generating units each have drive devices that can particularly preferably be controlled independently of one another. These drive devices can preferably have motor drives and in particular electromotive drives and in particular linear motor drives. For example, a linear motor that performs a piston movement can be provided. This linear motor can be connected to the piston device, which is described in more detail below.

The drive device can have a gear unit, for example a planetary gear. The drive device particularly preferably also has a spindle drive.

In a further preferred embodiment, the drive device also has a position detection unit which detects a position of a printing cylinder. In this way, the feeding of the liquid medium into the plastic preforms can be controlled and / or regulated in a targeted manner.

In a further advantageous embodiment, the pressure generating units each have a liquid space and a piston device which can be moved relative to this liquid space. By moving this piston device, the liquid is ultimately pressed into the containers here. In a further preferred embodiment, at least one pressure generating unit and preferably both pressure generating units are pump devices and in particular pump devices which are selected from a group of pump devices which include hydraulic pumps, sinus pumps, axial piston pumps, bellows pumps, membrane pumps, scroll pumps, rotary piston pumps, eccentric screw pumps, screw conveyors, impeller pumps, Chain pumps, annular piston pumps, peristaltic pumps, screw pumps, shaker pumps, toothed belt pumps and the like.

In a preferred embodiment, the compressed volume flows generated by the pressure generating units can be collected in the filling head which, in particular, is seated in a sealing manner towards the preform and particularly preferably ensures a constant flow front. The filling head preferably has a sealing plug which, depending on its position, can clear the way to the plastic preform. In addition, it would also be conceivable for the pressure generating units to have a piston device which can be pushed in again at least temporarily in order to generate pressure peaks in this way.

In addition, it would also be conceivable for different pressure levels to be implemented by the two pressure generating units, ring channels being particularly preferably available which serve to hold or store these different pressure levels. In this way it would be possible to achieve different pressure levels. For example, it would be conceivable for a first ring channel to have very large cross-sections possesses in order to provide such a small pressure level and to form the container as quickly as possible.

A second pressure level can have a very high pressure level in order to ensure that the container is shaped. For this purpose, an annular channel with a small cross section could be available. In this way, the two pressure stages could thus be collected in the filling head (i.e. the filling device).

In a further embodiment, it would also be possible to provide several pistons and / or cylinders in order to keep different products available in this way, for example to store them in the pressure cylinders and thus either to feed them mixedly to the filling device or to feed them individually.

Furthermore, it is also possible to provide higher volume flows with a constant torque reserve of the drives. If a drive is dimensioned larger, it is possible that the dynamics can no longer be implemented to the required extent and the drive cannot cope with the corresponding loads.

In addition, the invention would also make it easier to use a very wide range of volumes for customer objects. If, for example, a customer wants to produce a 0.5 l bottle, only one piston could be moved, for example, and with a 6.0 l bottle, for example, two or three pistons could apply the volume flow. In this way, it is possible to set a corresponding system in each case to different customer requirements, whereby it is preferably also possible to cover any maxima that may be required by a clever combination of the pressure generating units.

In a further advantageous embodiment, the filling device has a closing element which blocks an inflow of the liquid into the container in at least one position and allows this inflow in at least one position. This can be, for example, the abovementioned sealing plug which, depending on its position, can prevent or allow a flow of liquid into the plastic preform.

The present invention is furthermore directed to a method for expanding plastic preforms into plastic containers by means of a liquid medium and in particular directed by means of a filling material, wherein at least one forming station fills the plastic preforms with the liquid medium and expands and wherein the liquid medium is fed with at least one feed device of a filling device of the forming station, wherein the filling device fills the liquid medium into the plastic preforms, and wherein a pressure generating device of the Forming station supplies the liquid medium under pressure.

According to the invention, the pressure generating device has at least two pressure generating units which provide the forming station with the liquid medium under pressure.

It is therefore also proposed in terms of the method that the pressure for expanding the plastic preforms is provided by means of at least two pressure generating units. These pressure generating units preferably supply the pressure at least partially at the same time.

A device according to the invention for expanding plastic preforms into plastic containers by means of a liquid medium has at least one reshaping station which fills the plastic preforms with the liquid medium and expands. Furthermore, the device has at least one feed device which feeds the liquid medium to a filling device of this reshaping station, this filling device being suitable and intended for filling the liquid medium into the plastic preforms, and wherein the device has at least one pressure generating device, which the filling device the liquid Supplying medium under pressure.

According to the invention, the pressure generating device has a pretensioning device which pretensions at least one element of the pressure generating device.

In this embodiment, too, it is proposed to reduce the peak power, but here it is proposed in particular that at least one element of the pressure generating device, for example a piston device, is preloaded.

In order to reduce the load on the drive of the pressure generation, it is proposed to work with a preload of this drive. In particular, this is a translational preload.

In a preferred embodiment, the pressure generating device has a receiving space for the liquid medium and a piston device which is movable with respect to this receiving space in order to force the liquid medium to the filling device by a piston movement of this piston device. In this embodiment, the pressure generating device is designed as a movable piston or has such a piston.

Particularly preferably, the pretensioning device acts at least indirectly on this piston device and urges it in a predetermined direction. In particular, the pretensioning device urges the piston device in a direction which causes a reduction in the size of the receiving space and, in particular, a flow or urge of the liquid medium in the direction of the plastic preform to be expanded and filled.

In a further advantageous embodiment, the prestressing device prestresses the element of the pressure generating device in a translational direction. The piston device therefore preferably moves in a translatory or linear direction and the pretensioning device also effects a pretensioning in precisely this direction.

In a further advantageous embodiment, the prestressing device has a prestressing element which is selected from a group of prestressing elements which contains mechanical springs, permanent magnetic springs, pneumatic springs, hydraulic elements, linear motor elements, combinations thereof and the like.

For example, a mechanical spring could be provided which acts on the piston device, for example is articulated on a rear side of the piston device. In addition, the preload could also be designed as a hydraulic spring. For example, a hydraulic spring could be ensured via a prefeed pump. In addition, however, there could also be a rotational bias, for example in the form of a torsion spring. In addition, a separate pump could also be provided for the preload to create. It would also be conceivable to provide a pressure booster with compressed air for this purpose.

A pretensioning device preferably acts on a rear side of the piston device. However, it would also be possible for this pretensioning device to be carried out outside the pressure generating device, in particular in a separate cylinder which, for example, has a common axis with the pressure generating device or the filling piston.

It is pointed out that the embodiments described here can also be combined with the embodiments mentioned above. Embodiments are also conceivable in which two or more pressure generating devices are used and a pretensioning device is used. Instead of the term pre-tensioning device, the terms loading device or urging device can also be used.

In a further advantageous embodiment, the pretensioning device generates a pressure in the interior of a receiving space for the liquid medium that is greater than 2 bar, preferably greater than 4 bar, preferably greater than 6 bar and / or the pretensioning device generates a pressure inside the receiving space for the liquid Medium has a pressure that is less than 40 bar, preferably less than 30 bar and particularly preferably less than 20 bar.

The amount of (mechanical, pneumatic or hydraulic) prestressing is preferably chosen so that the molding times of the plastic preforms are reduced to a minimum with an overall system of the drive (for example an overall system of motor, spindle and prestressing).

In a preferred embodiment, the device has a pressure reservoir and in particular a pressure tank which feeds the respective bias. This can be the case in particular with hydraulic or pneumatic preloading. It is possible that the preload acts only temporarily, for example only supports it temporarily (for example only at the end or the beginning), or also brings about a (either constant or different) preload or support during the entire travel path.

In a further advantageous embodiment, the preload can be changed. It would be possible, for example, for the preload to be adapted to the expansion of different containers. It would be possible for the preload to be constant during the entire movement of the piston device, but it would also be conceivable that the preload changes during the movement of the piston or, for example, only occurs at certain time segments.

In other words, the amount of preload can have a fixed value (for example, it can be dynamically adaptable in the case of a mechanical spring (e.g. in the case of a pneumatic spring via the level of pressure) and / or switchable (e.g. pneumatic or hydraulic spring)).

In addition, it would also be conceivable for such a preload to be designed pneumatically and for a corresponding reservoir or tank to be so large that the support force is almost constant over the travel path.

In this way, the tank could be filled by moving the piston device up and down (especially when switching suitable valves, by compressing the air on the back of the filling piston or the preloading piston, thus producing at least part of the air required for a compensation tank .

However, the pressure could also be applied with pressure lines of different pressures, for example a 10 bar low pressure line or a 40 bar high pressure line.

In a further advantageous embodiment, the pressure generating device has a drive device, in particular an electric motor. This drive device can have a braking device which, if necessary, can block a movement of the piston device.

In a further advantageous embodiment, the pressure generating device has a piston device which is seated at least temporarily on a piston seat. In this case, the pre-tensioning force can be fed directly into the piston seat.

In a further advantageous embodiment, the pretensioning device can be switched off. For example, in the event of an emergency stop, the bias voltage can be switched off and / or a holding brake of a motor device, for example a servo motor, can be activated.

In an advantageous embodiment, the drive device for driving the cylinder device has a nut integrated in a rotor and a spindle (a hollow shaft).

A servo motor with an integrated spindle has many advantages in terms of installation space, weight, dynamics and flexibility. For example, connecting elements between the drive device and the linear screw could also be dispensed with.

In addition, it would also be possible for the drive device to be designed as a linear motor. A linear motor could be connected directly to the piston device in order to generate the driving force. In this case, too, a preload could also be applied.

In a further advantageous embodiment, the device could have a lever device which is suitable and intended to actuate two pressure generating devices or two cylinders. For example, the lever device could be a toggle lever that applies the required forces. A pressure curve when forming the container requires a rapid forming process and so a small path and large holding forces could be applied to an almost fully formed bottle. A toggle lever is particularly advantageous for such an application and is described in more detail below.

This toggle lever could, for example, be driven by a servomotor with a linear spindle or also optionally by a gear, or also by another drive unit that can be moved in the longitudinal direction or is rotatable. Here, too, a pre-tensioning can preferably be used, however, it is pointed out that this concept is also possible without the pre-tensioning described here.

Due to the geometry and the operating principle of a toggle lever, very high speeds can be achieved at the beginning of the travel path and thus also high volume flows, whereas towards the end and at the lower point of the piston drive the volume flows decrease and the force theoretically increases to infinity. In this way, high holding forces could also be achieved.

In addition, a hydraulic drive device could also be used as the drive device. Due to the high pressures that are common in hydraulics, the smaller cross-sections that are required to move a piston with a certain force could result in lower volume flows, which simplify a drive. For example, a hydraulic pump could pump the required volume flow, for example through a bypass, and, if necessary, pump it into the hydraulic cylinder. This would have a connection to the filling piston to be driven or the piston device.

The hydraulic cylinder could, however, also have a pump device that achieves the high level of dynamics, or also an axial piston pump in order to provide the required dynamics of the drive.

It would be possible to provide a system with a pump device and / or pressure generating device for each forming station, or also a device with one or more pump devices in parallel in order to be able to operate several stations from one hydraulic unit.

Overall, the preload offers the advantage that more possibilities in a drive calculation and also larger volume flows are possible with the same basic principle (piston or cylinder). The drive device is also cheaper than a larger drive without preload.

It is pointed out that in the following the pretensioning device is also shown as a loading device or as a force loading device which is suitable and intended to load the element of the pressure generating device in a predetermined direction.

The present invention is therefore further directed to a method for expanding plastic preforms into plastic containers by means of a liquid medium, wherein at least one reshaping station the plastic preforms with the liquid medium filled and expanded and wherein the liquid medium is fed with at least one feed device of at least one filling device of the forming station, wherein the filling device fills the liquid medium into the plastic preforms, and wherein a pressure generating device of the forming station supplies the liquid medium under pressure.

According to the invention, at least one element of the pressure generating device is pretensioned at least temporarily by means of a pretensioning device. Further advantages and embodiments emerge from the accompanying drawings.

Fig. 1

Eine grob schematische Darstellung einer erfindungsgemäßen Vorrichtung;

Fig. 2

Eine Darstellung einer Umformungsstation nach dem internen Stand der Technik der Anmelderin;

Fig. 3

Eine Darstellung einer erfindungsgemäßen Umformungsstation;

Fig. 4

Eine weitere Darstellung einer erfindungsgemäßen Umformungsstation;

Fig. 5

Eine Darstellung einer Druckerzeugungseinrichtung mit Kniehebel;

Fig. 6

Eine Darstellung einer Umformungsstation mit Vorspanneinrichtung;

Fig. 7

Eine Darstellung einer Umformungseinrichtung mit einer hydraulischen oder pneumatischen Antriebseinrichtung.

Show in it:

Fig. 1

A roughly schematic representation of a device according to the invention;

Fig. 2

A representation of a forming station according to the internal prior art of the applicant;

Fig. 3

A representation of a forming station according to the invention;

Fig. 4

Another illustration of a forming station according to the invention;

Fig. 5

A representation of a pressure generating device with a toggle lever;

Fig. 6

A representation of a forming station with a pretensioning device;

Fig. 7

A representation of a forming device with a hydraulic or pneumatic drive device.

Figure 1 shows a schematic representation of a device according to the invention for reshaping and filling containers. This has a rotatable carrier 12 on which a plurality of forming / filling devices are arranged. As mentioned above, these shaping devices serve to fill the plastic preforms with a container and to expand them at the same time. Via a feed device 15, such as a feed star, plastic preforms are fed to the device and the finished and Filled containers are then transported away from the device via a discharge device 17.

Figure 2 shows a forming station 2 according to the internal prior art of the applicant. The actual filling device is provided here, which has a loading device 25 which can be placed against an opening 10a of the plastic preforms to be expanded in order to fill and shape the plastic containers 10. For this purpose, the reshaping device has an expansion mold 11, within which the plastic preforms are expanded to form the plastic bottles or plastic containers. The reference numeral 26 denotes a filling housing, within which a closing device 24, such as a closing plug, is arranged. By moving this valve body in the longitudinal direction L of the container, the supply of liquid into the container 10 can be regulated.

The reference number 22 denotes a so-called stretching rod which can be inserted into the interior of the containers in order to stretch them in their longitudinal direction. For this purpose, the device has a drive device 27 which is suitable and intended to move the stretching rod in its longitudinal direction.

The reference numeral 4 designates in its entirety the pressure generating device which supplies the liquid under pressure to the plastic container. Here, this pressure generating device has only one pressure generating unit. This pressure generating device, more precisely the pressure generating unit, has a receiving space 45 within which the liquid 47 to be filled is provided. In addition, feed lines can also be provided which (for example, starting from a reservoir (not shown)) feed the liquid to the receiving space 45.

The reference numeral 43 denotes a piston device which is movable in the direction x in order to transport the liquid via a connecting line 35 to the actual filling head (also referred to above as the filling device). The reference numeral 62 identifies the drive device, in particular in the form of a servomotor 63 which drives the movement of the piston device 43. For this purpose, the drive device generates a rotary movement which is output via an output shaft 64. The reference number 65 denotes a gear device, such as a planetary gear here, and the reference number 66 another output shaft. This output shaft in turn drives a linear spindle 67 and this moves rod elements 68 and 69, which are connected via a coupling and on which the piston device is in turn arranged.

Therefore, the in Figure 2 The embodiment shown, the device only has a single pressure generating device, which has to apply the pressure for filling and expanding the containers. The reference symbol 32 denotes a pressure measuring device which measures a pressure occurring in the filling housing 26.

Figure 3 shows an embodiment of a device or forming station 2 according to the invention. Here, the actual filling head is constructed in a manner similar to that in the embodiment shown in FIG. 2, and is therefore not explained in more detail. In contrast to the in Figure 2 However, two pressurization units 42 and 44 are provided here. These can be structured in the same way and have already been described above, so this is not repeated. It is possible that these pressurization units work at the same time, but they can also fill the containers with a liquid medium in an offset manner. In addition, it would also be possible for these two pressurization units 42 and 44 to receive different liquids in their respective receiving spaces 47 and thus, for example, a mixed product to be fed to the container 10.

Figure 4 shows an embodiment in which a total of four pressurization units 42 to 44 are present, which are also connected again to the actual filling device via connecting lines. These four pressure generating units can contain several different products, for example four different products. In this case it would be possible that the driving force is again minimized and a product mixture is also filled. It is possible here for a product to be present in each of these pressure generating devices which is pressed into the plastic preform to be reshaped either simultaneously or one after the other via the actual filling device. The drive power required for one of these four pressure generating units could be significantly reduced compared to the power requirement when using only a single pressure generating unit.

In addition to or instead of the drive devices described above, however, hydraulic drive devices could also be provided, or also motors with a nut integrated in the rotor and a spindle, which is designed, for example, as a hollow shaft.

Figure 5 Figure 3 shows another embodiment of the present invention. In this embodiment, two pressure generating units 42 and 44 are also provided, although the actual filling devices are not shown here. In this embodiment, only a drive of the type described above is provided, but also a lever device 50 which transmits the forces thus generated to the piston devices 43. This lever device is designed here as a so-called toggle lever, which is articulated to both piston devices 43 in order to move them in this way. In this case, the required forces are applied with a toggle lever. The pressure curve when forming the containers here requires a fast forming process and, when the bottle is almost fully formed, a short path and high holding forces.

Figure 6 Figure 3 shows another embodiment of the present invention. In this embodiment, the actual filling device is constructed similarly to the filling device mentioned above. The drive device 62-69 is also constructed similarly to the above and is therefore no longer described. In addition, the in Figure 6 However, the device shown has a pretensioning device on or a preloading device 7, which pretensions the piston device 43 in the direction x downwards. In the embodiment shown here, this pretensioning device has a reservoir 72 in which, for example, air can be stored under a certain pressure. This air can be fed into the space 78 via a connecting line 74 and a valve 76. In this receiving space, the pressurized air can additionally load the piston device 43, so that it is forced downwards.

This means that the in Figure 6 The embodiment shown, the contact surface or the contact area for the pretensioning device, the rear side of the piston device 43.

Figure 7 shows a further embodiment of the device according to the invention. In this embodiment, too, the actual filling device is designed in the manner shown above. Here, too, there is again a receiving space 47 and a piston device which is movable with respect to this receiving space. In the Figure 7 The design shown differs by the type of drive for the piston device. A hydraulic or pneumatic drive device is used here as the drive device. For this purpose, a hydraulic space 94 is again provided here, in contrast to which a piston element 92 can also be moved in the direction x. The reference numeral 98 denotes a piston rod, which in turn is coupled to the piston device 43 by means of a coupling device.

Reference numeral 82 denotes a valve which can be switched in a controlled manner. By precisely switching this valve 82, a volume could be set in a time-controlled manner. In addition, mechanical stops or a changed volume flow of a pump would also be conceivable within this drive device 90. Reference numeral 84 denotes a corresponding hydraulic pump which is connected to valve 82 via a connecting line 86. The valve can be controlled in such a way that it can lead a hydraulic medium both into the space section 96 and into the space section (or hydraulic space) 94. It is also conceivable that the hydraulic drive unit 90 described here would only have to be connected to the piston device 43 by means of a rod and that in this way components that are highly contaminated have no direct connection. Reference numeral 85 denotes a connecting line.

A wide variety of pump types from the prior art could be considered as the hydraulic pump. In addition, the coupling device 95 between the piston rod 98 and the filling piston rod 69 can also bring about a real separation of the components.

The device therefore generally has a coupling device which couples at least one element of the drive unit to at least the piston device.

Due to the preload described here, which is also due to the in Figure 7 The embodiment shown or the variant can be achieved, several tasks are fulfilled. In this way, the drive device is cheaper than a corresponding larger drive without a preload. In theory, a pressure connection can also be dispensed with.

The use of a hydraulic drive unit has the advantage that it usually has smaller dimensions. In addition, faster switching times can often be achieved and components known or prefabricated from the prior art can be used.

List of reference symbols

1

contraption

2

Forming station

4th

Pressure generating device

6th

Drive device

7th

Prestressing device, loading device

10

Plastic containers

10a

mouth

11

Expansion form

12th

rotatable carrier

15th

Feeding device

17th

Discharge device

22nd

Horizontal bar

24

Locking device

25th

Charging device

26th

Filling housing

27

Drive device

32

Pressure measuring device

35

Connecting line

42, 44

Pressure generation unit

43

Piston device

43a, b

Pressure generation unit

45

Recording room

47

liquid to be filled

50

Lever device

62

Drive device

63

Servo motor

64

Output shaft

65

Transmission device

66

Output shaft

67

Linear spindle

68

Bar element

69

Bar element

69

Filling piston rod

72

reservoir

74

Connecting line

76

Valve

78

space

82

Valve

84

hydraulic pump

85

Connecting line

86

Connecting line

90

Hydraulic drive unit

92

Piston element

94

Hydraulic room, room section

95

Coupling device

96

Room section

98

Piston rod

x

direction

Claims (9)

1. An apparatus (1) for expanding plastic preforms (2) into plastic containers using a liquid medium having at least one forming station (2) that fills and expands the plastic preforms using the liquid medium using at least one supply device (42, 44, 35) that supplies the liquid medium to a filling device of this forming station (2), wherein said filling device (24, 25, 26) is suitable and destined to fill the liquid medium into the plastic preforms (10), and wherein the apparatus has a pressure generation device (4) that supplies the liquid medium under pressure to the filling device (24, 25, 26), wherein the pressure generation device (4) has at least two pressure generation units (42, 44) suitable and designed to provide the liquid medium under pressure to the filling device (24, 25, 26), characterised in that
   the pressure generation units (42, 44) each have drive devices (6) that can be controlled independently of each other.
2. The apparatus (1) as claimed in claim 1,

   characterised in that

   the two pressure generation units (42, 44) are connected in parallel in such a way that they each supply the liquid medium to the filling device.
3. The apparatus (1) as claimed in at least one of the preceding claims,

   characterised in that

   the two pressure generation units (42, 44) are each connected to the filling device (24, 25, 26) via liquid lines (35).
4. The apparatus (1) as claimed in at least one of the preceding claims,

   characterised in that

   the filling device has a collection space for receiving the liquid medium, which collection space is in fluid communication, at least temporarily, with each of the pressure generation units (42, 44).
5. The apparatus (1) as claimed in at least one of the preceding claims,

   characterised in that

   the pressure generation units (42, 44) each have a liquid chamber (47) and a piston unit (43) that can be moved relative to this liquid chamber.
6. The apparatus (1) as claimed in at least one of the preceding claims,

   characterised in that

   at least one pressure generation unit (42, 44) is a pump unit and in particular a pump unit that is selected from a group of pump units consisting of hydraulic pumps, sinus pumps, axial piston pumps, bellows pumps, diaphragm pumps, scroll pumps, rotary piston pumps, eccentric screw pumps, screw conveyors, impeller pumps, chain pumps, annular piston pumps, hose pumps, screw spindle pumps, shake pumps, tooth belt pumps and the like.
7. The apparatus (1) as claimed in at least one of the preceding claims,

   characterised in that

   the filling device (24, 25, 26) comprises a closure element (24) that blocks the flow of the liquid into the container in at least one position and allows this flow in at least one position.
8. The apparatus (1) as claimed in at least one of the preceding claims,

   characterised in that

   the pressure generation device has a toggle lever.
9. A method for expanding plastic preforms (10) into plastic containers by means of a liquid medium using at least one forming station (2) that fills and expands the plastic preforms using the liquid medium, wherein the liquid medium is supplied to a filling device of the forming station (2) using at least one supply device, wherein the filling device fills the liquid medium into the plastic preforms (10) and wherein a pressure generation device of the forming station supplies the liquid medium under pressure, wherein the pressure generation device (4) has at least two pressure generation units (42, 44) that provide the liquid medium under pressure to the forming station,

   characterised in that

   the pressure generation units (42, 44) each have drive devices (6) that can be controlled independently of each other.

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